Mistake in Tefillin

In a post last week, I wrote about having Mezuzahs and Tefillin checked by computer. I wrote that nowadays, almost all things sold have undergone the computer check. Therefore, I wrote, it is quite rare to find an actual textual mistake these days.

After I wrote that post, I checked a pair of Tefillin and found an extra letter. I thought I would share it with you.  

As you can see, the mistake is circled in red. There is a superfluous letter Yud at the beginning of the word "Shivat".

It would be interesting to find out how this mistake got overlooked. It may be because it was sold by someone who didn't bother to have it computer checked. It is more likely though that it was mistakenly put in a box of things that had already been checked, even though it wasn't checked yet. It just goes to show that even though the computer check is a very valuble tool, there is still no replacement for having your Mezuzahs and Tefillin checked regularly by a trained Sofer.